[rdnicolas]

Originally Posted by untamed

I think you have your answer right there. If you have been mixing new SW the day before, that gives the water time to "breath off" the Chlorine. You might check to see if your area uses Chloramine, which is even stronger and more toxic (I think).

Anyway...the Chlorine remover you've been using may not have been working as you think for some time. Or, it might have been removing some CL and 24hrs was doing the rest for you. When you didn't provide that time to vent the Chlorine in the new SW, that poisoned the tank.

Of course, we all know that if you kill enough things quickly, you cause a chain reaction of death.

I think this is what happened then. Probably combination of chlorine and lack of oxygen. Ill probably do another water change but I'll wait until tomorrow for the water to settle in this time.